The invention relates to a safety lock for an elevator landing door detecting intrusion of a person in the shaft through the landing door and the elevator thus equipped.
It is known that some elevator landing door locks are provided with a bistable safety switch activated by the landing door lock key when the door is opened, and putting the elevator into safe operation, such that it is impossible to do a manual reset from inside the shaft. Nevertheless, the switch position is reset electrically from the elevator machine room. This arrangement requires an electrical reset actuation device for the bistable switch and the corresponding wiring for the landing door in the elevator machine room. Moreover, during maintenance operations, the operator needs to perform a painstaking procedure for resetting in the elevator machine room and the corresponding to and fro movements.
An embodiment of the invention is designed to overcome these disadvantages and comprises a safety lock for an elevator landing door detecting intrusion of a person in the shaft through the landing door, activating a bistable switch through its spindle lever putting the elevator into safe operation when the landing door is opened by turning the corresponding key, it being impossible to reset the switch manually from the inside of the shaft, characterized in that it comprises a device fixing the lock in the open position with the door open, that is released when the door is closed such that the switch can be reset by turning the lock in the closing direction of the door in which the key is turned in the opposite direction to the opening direction, the switch being reset mechanically by a mechanical means connected to the spindle lever.
The bistable switch is of the type comprising an actuation tab or a lever projecting outwards moved by turning the lock from a first reset position in which the elevator is controlled in normal service to a second position when the door is opened in which the elevator is controlled in safe operation, and brought back to the rest position when the switch is reset, in a maneuver to closing the lock, with the door closed.
The bistable switch is protected from manual access by a casing covering it. Its position on the door lintel behind the landing door coupling plate activated by the lock, makes it even more difficult to access.
When the spindle lever is in the rest position, apart from reaching the coupling plate, through at least one spiral or helical spring wound around the lever spindle and bearing on the lintel through its two end strands arranged on each side of the spindle, advantageously it is the end strand of the spring close to the switch activation tab, which is lifted when the door lock opens and moves the switch tab from its first position to the second position in which the elevator is put into safe operation.
The at least one spring preferably composed to two spiral or helical springs wound fixed around the lever spindle and in which the external strands bear on the lintel at rest on each side of the lever spindle, the strand closest to the switch actuation tab being turned to contact towards it when the lock opening maneuver is performed.
The switch actuation tab may be actuated to move into its second position by an elastic tab or lever replacing the end strand of the spring fixed to the lock lever spindle in rotation and engaging on the switch actuation tab during opening.
The mechanical means connected to the spindle lever of the lock is advantageous composed of a rear tab fixed to the spindle lever of the lock and moving the switch actuation tab in its rest position, when the lock is turned closed, when the door is closed.
The device for locking the lock open, with the door open, formed in one example by creating a groove on the lock bushing fixed to the door lintel, in which a complementary mobile part fits into the groove, pulled towards it and locking the lock in the open position, this mobile part being pulled outside the groove by a mobile stop fixed to the landing door support carriage, arranged in the appropriate position to push the said mobile part outside the bushing groove when the landing door is closed.
The bushing preferably comprises at least one heel cooperating with the mobile complementary part in locking, during opening.
The mobile part is advantageously a plate installed free to pivot close to the lock bushing and pulled towards it by a spring, it being released by the plate being pushed by the said door carriage stop.
An embodiment of the invention also relates to an elevator equipped with at least one safety lock like that described above.